Revision: 25125
Author: [email protected]
Date: Wed Nov 5 06:20:36 2014 UTC
Log: Set the FPU precision control to double-precision.
The default double precision control of FPU is extended double-precision.
While the number definition for JavaScript is double-precision. We use
the FPU control word to set the doulbe precision and replace the original
solution which store the data to memory and load it again.
This patch also fixes the error that Sunspider 1.0.2 can not run with V8 if
sse2 support is disabled.
BUG=
[email protected]
Review URL: https://codereview.chromium.org/700053003
Patch from Chunyang Dai <[email protected]>.
https://code.google.com/p/v8/source/detail?r=25125
Modified:
/branches/bleeding_edge/src/x87/lithium-codegen-x87.cc
/branches/bleeding_edge/src/x87/macro-assembler-x87.cc
/branches/bleeding_edge/src/x87/macro-assembler-x87.h
=======================================
--- /branches/bleeding_edge/src/x87/lithium-codegen-x87.cc Tue Oct 21
08:28:00 2014 UTC
+++ /branches/bleeding_edge/src/x87/lithium-codegen-x87.cc Wed Nov 5
06:20:36 2014 UTC
@@ -2272,6 +2272,8 @@
if (instr->op() != Token::MOD) {
X87PrepareBinaryOp(left, right, result);
}
+ // Set the precision control to double-precision.
+ __ X87SetFPUCW(0x027F);
switch (instr->op()) {
case Token::ADD:
__ fadd_i(1);
@@ -2306,12 +2308,8 @@
break;
}
- // Only always explicitly storing to memory to force the round-down for
double
- // arithmetic.
- __ lea(esp, Operand(esp, -kDoubleSize));
- __ fstp_d(Operand(esp, 0));
- __ fld_d(Operand(esp, 0));
- __ lea(esp, Operand(esp, kDoubleSize));
+ // Restore the default value of control word.
+ __ X87SetFPUCW(0x037F);
}
=======================================
--- /branches/bleeding_edge/src/x87/macro-assembler-x87.cc Mon Oct 20
04:06:06 2014 UTC
+++ /branches/bleeding_edge/src/x87/macro-assembler-x87.cc Wed Nov 5
06:20:36 2014 UTC
@@ -765,6 +765,13 @@
fldcw(MemOperand(esp, 0));
add(esp, Immediate(kPointerSize));
}
+
+
+void MacroAssembler::X87SetFPUCW(int cw) {
+ push(Immediate(cw));
+ fldcw(MemOperand(esp, 0));
+ add(esp, Immediate(kPointerSize));
+}
void MacroAssembler::AssertNumber(Register object) {
=======================================
--- /branches/bleeding_edge/src/x87/macro-assembler-x87.h Mon Oct 13
14:41:33 2014 UTC
+++ /branches/bleeding_edge/src/x87/macro-assembler-x87.h Wed Nov 5
06:20:36 2014 UTC
@@ -425,6 +425,7 @@
void FXamSign();
void X87CheckIA();
void X87SetRC(int rc);
+ void X87SetFPUCW(int cw);
void ClampUint8(Register reg);
void ClampTOSToUint8(Register result_reg);
--
--
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